Referring to FIG. 10, a conventional selective one-way wrench 110 includes a handle 114, an annular head 115, an annular gear 120, a pawl 130 and a switch 140. The annular head 115 is formed at an end of the handle 114, the annular head 115 defines a first space 111, a second space 112 communicated with the first space 111 and a third space 113 communicated with the second space 112. The annular gear 120 is rotationally put in the first space 111. The annular gear 120 includes a toothed external face 121 formed thereon and a toothed internal face 122 for engagement with a bolt or nut. The pawl 130 is put in the second space 112. The pawl 130 includes a toothed side 131 formed thereon. The switch 140 is rotationally put in the third space 113 of the handle 114 and partially put in the second space 112 for bringing the toothed side 131 of the pawl 130 into engagement with the toothed external face 121 of the annular gear 120.